Multipack photography



AJuly 23, 1940.

J. EGGERT ET AL MULTIPACK PHOTOGRAPHY Filed Dec. ll, 1935 fo/zn EggertAmaai mm Bz'ehr Gerd Hfeymer By /zeir Aharneys l Patented July 23, 1940MULTIPACK PHOTOGRAPHY John Eggert, Leipzig-Gohlis, Arpad von Bichler,

Dessau,

and Gerd Heymer, Wolfen Kreis Bitterfeld, Germany, assignors, by mesneyassignments. to.Genera'l Aniline & Film Corporation, New York, N. Y., acorporation of Dela- Ware Application December 11, 1935, Serial No.53,872

In Germany December 13, 1934 1 Claim. This invention relates tomultipack photography.

' sion layers sensitized for One of its objects is a multipack withwhich sharper pictures are obtainable than hitherto usual. Furtherobjects will be seen from the detailed specification followinghereafter.` Reference is made to the accompanying drawing in which Fig.l shows a tripack of normal film and Fig. 2 shows a lenticular bipack inaccordance with the invention.

In the production of multicolor pictures by means of the usual biandtripacks, there is placed in front of the second and third layer,respectively, in thepack a yellow or red filter in some suitable form,for instance, as an intermediate separate iilm or as a colored coatingon the emulsion side or the opposite side of the support, or the carrieritself may be colored. The emulsion layers behind this filter are thussensitized for corresponding kinds of light. The light filtersconsisting of separate films or layers interposed in the pack have thedisadvantage that the distance between the several emulsion layers isincreased, so that the rear pictures produced are not so sharp as theremainder. The colored support does not present this drawback but thesupport cannot subsequently be decolorized and therefore renders thepicture unsuitable for copying. i

According to this invention there is used a fine-grained emulsion, richin silver, which is differently sensitized for each layer, so as toproduce the desired color separation. it being a'dvantageous to damp thespecific blue sensitivity of the emulsion by the known method ofdirectly dyeing the emulsion with a screening dye, for instance, ayellow dyestui. The grain of the emulsion layers in the multipack shouldnot exceed a mean value of la diameter and the ratio of silver togelatin should be at least l part of silver ony 1,5 parts of gelatin thepartsV being by weight.

The material made by the invention is therefore without any coloredlayer between the emuldifferent spectral ranges; this is a, substantialsimplication in the manufacture and leads to improved sharpness in therear picture. The invention is applicable forV all tripack arrangements;advantageously it is combined with. the invention de-l scribed in U. S.patent application Serial4 No. 48,337, which deals with the'productionof pictorial swollen reliefs from thin, extremely highly hardened layersof emulsion. In the tripack according to this invention the bluesensitive film is preferably arranged next the source of light, whereasthe films sensitive to green and red may follow in optional manner.

The invention is also useful in the production of the two-packlenticular lm described in U. S.

PatentNo. l1,968,944. In this case the resolution into the fundamentalcolors is produced in part by the iilter and screen and. in part by aspectral method with the advof diiferently colored and sensitizedlayers. The use of iinelygrained layers rich in silver makes itunnecessary in this case to introduce a red filter layer as has hitherto'been usual, whereby, moreover, the assistance of the two-Zone lterarrangement in front of the objective still favours the sharp separationbetween the red and green details.r

In this manner there is obtained a separation of the fundamental colorswhich is better than when filters or sensitizers are used alone.

Fig. 1 of the accompanying drawing shows a tripack consisting of threenormal films, I. 2 and 3. The front film I is sensitive to' blue, themiddle film 2 is sensitive to green and the back lm is sensitive to red.Fig. 2 shows a lenticular bipack in which the lenticular front lm l issensitive to blue and green, and the smooth back lm 2 is sensitive tored.

What we claim is:

A combination of a multipack consisting of' a lenticular film in contactwith a smooth lmv and not being separated by any filter layers, each vlmconsisting of a support coated with a silver halide gelatin emulsionlayer having a grain size not exceeding a mean value of la diameter, the

ratio of silver to gelatin being at least l part of silver on 1.5 partsof gelatin, the parts bein'gby weight, and the .two emulsion layersbeing sensitized to different spectral regions.

l JOHN EGGERT.

ARPA'D von BIEHLER. GERD HEYMER..

